EP0076688A1

EP0076688A1 - Telephone answering and message recording system

Info

Publication number: EP0076688A1
Application number: EP82305277A
Authority: EP
Inventors: Iwao Sagara
Original assignee: Oki Electric Industry Co Ltd
Current assignee: Oki Electric Industry Co Ltd
Priority date: 1981-10-05
Filing date: 1982-10-04
Publication date: 1983-04-13
Also published as: JPS5859657A; JPS6352832B2; US4518827A; EP0076688B1; DE3264439D1

Abstract

A telephone answering and message recording system comprises a microphone (4), an analog-digital converter (6) for converting the analog speech signal of the microphone (4) to a digital signal, a digital memory (M₁, M₂, M₃, M₄, MEM,-MEM_n) for storing the digital speech signal from the converter (6), a digital-analog converter (7) for re-converting the digital signal of the output of the memory to an analog signal, and a speaker (5) coupled to the output of the digital-analog converter (7). The system also comprises a PB (push button) code receiver (40) for detecting a PB code which is the combination of two frequencies. The operational mode and/or the memory to record or reproduce speech is switched by the particular PB code. The system may operate in a first, fixed answering, mode in which a fixed answer recorded in the memory is transmitted to a remote subscriber or in a second, adaptive oral communication, mode in which speech recorded in the memory can be revised and/or transmitted to a remote subscriber through a telephone line. In the latter mode, two remote persons may communicate with each other through the system even when those two persons do not call the system simultaneously.

Description

This invention relates to a telephone answering and message recording system, and in particular to such a system which uses a solid-state memory or a semiconductor memory for recording speech and can operate in a two-way oral mode.
Conventionally, a telephone answering system uses an elongate magnetic tape for recording speech, and the magnetic tape is usually wound on a reel.
However, a prior telephone answering system with a magnetic tape has the disadvantages that it takes a long time to rewind the tape, it is difficult to find the position of the start of the speech on the tape when playing back, two tape recorders must be used when a two-way oral communication is carried out, and/or only one mode of recording or playback is available at a time.
It is an object of the present invention to provide a new and improved telephone answering and message recording system.
According to the invention, a telephone answering and message recording system including communication and selection circuitry comprising a microphone;a speaker; an analog-digital converter for converting an input analog speech signal from the microphone or from a telephone line to a digital signal; a plurality of groups of semiconductor memories, each group having a plurality of memory cells; a group selection switch coupled to the output of the analog-digital converter to select one of the groups; a cell selection switch coupled to the output of the group selection switch to select one of the memory cells in each selected group; an output . switch coupled to the outputs of the memories of the groups to select one of the groups; a digital-analog converter coupled to the output of the output switch,the output of the digital-analog converter being coupled to the speaker; the system further comprising a call detector to detect reception of a telephone call to initiate operation of the communication and control circuitry; a plurality of manual switches for operating each group of memories; and means for controlling the operation of the communication and control circuitry according to a predetermined sequence.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:

Fig.l is a block diagram of a telephone answering and message recording system according to the invention,
Fig.2 is a schematic pictorial view showing the appearance of the system, and
Figs.3A and 3B illustrate the operational timing sequences of the system.

Referring to Fig.l, an electro-magnet 1a is provided for lifting a handset of a convention telephone 1 when a call to the telephone arrives. A call detector 2 detects the reception of a telephone call and initiates a control circuit 16 of the present system. A switch 3 switches modes between the ordinary telephone mode (without the present system) and a telephone answering mode (using the present system). A microphone 4 picks up both oral speech in front of the microphone and sound from the receiver of the handset of the telephone 1. A speaker 5 may transmit sound to a person using the system and to the microphone in the handset of the telephone 1.
The system may be coupled to a telephone line either through acoustical coupling or through electrical coupling. The figures show the use of acoustical coupling, in which the handset is lifted by the electro-magnet la when a call is connected to the telephone set, and the handset is acoustically coupled to the microphone 4 and the speaker 5. In the case of electrical coupling, the handset is not lifted,but the lines to the microphone and the speaker are coupled to a telephone line through an electrical switch (not shown).
Referring also to Fig.2, a housing 100 of the system has four units M₁, M₂, M₃ and M₄. The system has two operational modes, a first fixed answering mode, and a second adaptive oral communication mode. The first mode uses the units M₁ and M₂, and the second mode uses the units M₃ and ^M ₄.
The unit M₁ has an A-switch 21 with two positions RESET and REPRODUCTION, and a numeral indicator 21-a. This unit is concerned with the message recording function; and memories associated with the unit M₁ record the speech of the caller. When the A-switch is in the REPRODUCTION position, the content of the memories, i.e. the recorded speech, is reproduced through the speaker 5, and the user can listen to the recorded message. The system has a plurality of channels of memories which can record a plurality of speech signals, and it is assumed that the contents of the channels are reproduced in sequence. When the A-switch is set in the RESET position, the content of the memories is cleared or erased. The numeral indicator 21-a indicates the number of calls which were received by the system during the user's absence.
The unit M₂ is concerned with recording of the master speech which is transmitted to a remote person who calls the system. A plurality of memories is associated with the unit M₂, and the content of those memories is transmitted to the telephone line at a predetermined interval. The unit M₂ has a B-switch 22 with RECORD and REPRODUCTION positions, and an indicator lamp 22-a. When speech is to be recorded, the B-switch 22 is set to the RECORD position, and speech on the microphone 4 is recorded in the associated memories. During the recording operation, the indicator lamp 22-a lights to indicate that operation. When the B-switch 22 is in the REPRODUCTION position, the recorded content in the memories is reproduced through the speaker 5 for monitoring purposes. The B-switch is kept in a neutral position when the system is coupled to a telephone line for on-line operation.
The unit M₃ is concerned with recording the speech of a caller selectively into a selected memory. Selection of the memory is accomplished by a particular PB code which is the combination of two frequencies of a push button signal. The unit M₃ has a C-switch 23 having RESET and REPRODUCTION positions, a numeral indicator 23-a which indicates a selected channel or a selected memory, and a push button switch 23-b which, when pressed, increments the indication of-the numeral indicator 23-a. When the C-switch is in the REPRODUCTION position, the content of the memory indicated by the indicator 23-a is reproduced through the speaker 5, and channels to be reproduced are switched sequentially upon depressing the button switch 23-b. When the C-switch is in the RESET position, the content of the memory indicated by the indicator 23-a is erased. The C-switch is kept in a neutral position when the system is coupled to a telephone line.
The unit M₄ is concerned with recording local speech into a selected memory. Selection of the memory is accomplished by the PB code. The unit M₄ has a D-switch 24 which has RECORD and REPRODUCTION positions. When the D-switch is in the RECORD position, local speech reaching the microphone 4 is recorded in the memory which is selected by the PB code beforehand. When the D-switch is in the REPRODUCTION position, the content of the memories is reproduced through the speaker 5 for local monitoring - purposes.
In the block diagram of Fig. 1, a speech signal at the microphone 4 in analog form is applied to an analog-digital converter 6, which converts the signal to digital form. The digital speech output signal of the analog-digital converter 6 is applied to one of the memory groups of the units M₁, M₂, M₃ and M₄, according to operational mode, via a group selection switch 6a and one of switches 110,120, 130 and 140. The switch 6a selects the unit M₁ when the system is in a fixed answering mode to record remote speech, and selects the unit M₂ when the B-switch 22 is set in the RECORD position to record local speech in the fixed answering mode. On the other hand, the switch 6a selects the unit M₄ when the system is in an adaptive oral communication mode which is initiated by the PB code detected by a PB receiver 40. The combination of the two frequencies of the PB code causes the switch 6a to select the unit M₃ or M₄₁ and then to select one of the memories MEM₁ to MEM_n in the unit according to the particular PB code. Therefore, it should be appreciated that each PB code and its related memory (MEM₁ to MEM_n) may relate to a particular person who uses the system. In other words, when the PB code is a first code (f_l,f₂), the speech of the output of the A/D converter 6 is recorded in the first memory MEM₁ of the unit M₄, and when the PB code is a second code (f₁,f₃), the speech is recorded in the second memory MEM₂ in the unit M₄.
The switch 6a selects the unit M₃ when the system is in an adaptive oral communication mode (when the PB code is received), and the D-switch 24 is in the RECORD position, so that local speech is recorded in one of the memories in the unit M₃. When the unit M₃ is selected, local speech on the microphone 4 is recorded in one of the memories MEM₁ to MEM_n which is designated by the PB code detected by the PB receiver 40 in the unit M₃. In the unit M₃, each memory MEM₁ to MEM_n and/or the related PB code concerns a particular person who uses the present system.
An output switch 7a selects one of the outputs of the memory groups according to the operational mode, and the selected memory output is applied to a digital-analog converter 7, which converts the digital signal to an analog signal. The converted analog signal is applied to the speaker 5 to provide an oral sound signal.
The control circuit 16 provides control pulses to operate the units (including the memories and the switches 6a, 7a, 110, 120, 130 and 140) according to a predetermined sequence. The control circuit 16 is initiated by the output of the call detector 2. The circuit 16 is implemented either by wired logic hardware or by a programmed computer.
A control 30 controls the memories of the units M₁ and M₂ when those units are operative. A control 32 controls the memories of the units M₃ and M₄ when those units are operative.
Next, the timing of the operation of the system will be described with reference to Figs.3A and 3B.
In a first fixed answering mode it is assumed that at least one fixed local speech is recorded in the memories MEM₁ to MEM_n in the unit M₂, and the content of the memories MEM₁ to MEM is reproduced with a predetermined interval which is adjustable by a timer (not shown), or the sequence control of the read-out timing of the memories MEM₁ to MEM_n by the control circuit 16. An example of the fixed local speech is "This is Ratner speaking", or "who is speaking?".
The system operates with a clock signal which has a predetermined short interval (Fig.3A(a)).
In the fixed answering mode, when the system is called the bell of the telephone rings three times (see Fig.3A(b)). When the bell has rung three times, the call detector 2 recognises reception of a call (Fig.3A(c)) and initiates the system to the fixed answering mode (Fig.3A(d)), and an operation start pulse is provided by the control circuit 16 (Fig.3A(e)). The start pulse of Fig.3A(e) causes the control 30 to operate (Fig.3ACf)). At the initial stage, the unit M₂ is set to the reading mode, and the unit M₁ is set to the writing mode, and then the system begins to operate.
The content C₁ of the first memory MEM₁ in the unit M₂ is read out (Fig.3A(g)) and is transmitted to a remote subscriber. After a predetermined interval (T), the content (C₃) of the second memory MEM₂ of the unit M₂ is transmitted (Fig.3A(i)) to the remote subscriber. The remote subscriber answers C₂ to the first fixed speech C₁. Therefore, the conversation will be as follows.

C₁: This is Ratner speaking. Who is speaking?
C₂: This is Sagara.
C₃: I am not in just now. Please record your message in this recording system.
C₄: When you return home, please call me.

The unit M₁ records both the remote speeches C₂ and C₄, and the fixed local speeches C₁ and C₃ so that the complete stream of the conversation may be reproduced by listening only the unit M₂.
The interval T between successive local speeches (see Fig.3A(h)) may be determined by (1) a timer, (2) sequence timing control by the control 16 for reading out the memories, or (3) the level detector 18 and the timer 19. In the third case, when the level detector 18 and the timer 19 detect that the signal level is lower than a predetermined level for a predetermined duration, it is determined that the remote speech is finished, and the pulse signal of Fig.3A(h) is provided by the timer 19, and then the local speech C₃ begins.
When a remote speaker finishes the whole speech and puts the handset down, the call detector 2 detects the end of the speech and provides an end pulse (Fig.3A(k)), which terminates the operation of the system by having the control 16 provide a reset pulse (Fig.3A(1)). That reset pulse (Fig.3A(l)) terminates the whole operation of the system, and the recording operation of the unit M₁ is also finished.
In a second adaptive oral communication mode, it is assumed that a plurality of fixed local speeches are recorded in each of the memories MEM₁ to MEM_n in the group M₄ according to the particular person and/or the particular PB code. When the present system is used in a family, examples of the local speeches might be:

MEM₁ (Mother) : I went to the supermarket.
MEM₂ (Father) : I went to the company.

In the adaptive oral communication mode, when the bell rings three times (see Fig.3B(a)), the call detector 2 (Fig.2) detects reception of a call, and initiates the system to the fixed answering mode. Then the unit M₂ is set to the read mode, and the unit M₁ is set to the record mode. The content C₁ of the unit M₁ is then read out, and the local speech "This is Ratner speaking. Who is speaking?" is transmitted to the remote subscriber.
However, that local speech C₁ is interrupted upon receipt of the PB code which is detected by the PB receiver 40. The PB code has the combination of two frequencies of a PB signal of a push button telephone system. When the PB receiver 40 detects one of the PB codes, the receiver controls the switches 6a and 7a so that the switch 6a selects the unit M₃, and the switch 7a selects the unit M₄. Hence, upon receipt of the PB code, the operational mode is switched from the fixed answering mode to the adaptive oral communication mode.
A remote subscriber can transmit a PB code by operating a conventional key pad or a PB pad, which provides a sound having two frequencies.
In Fig.3B, when the remote subscriber depresses a key pad to transmit the particular PB code (f_n, f_n') the operational mode is switched. The fixed speech C₁ is interrupted, and a new speech D₁ is transmitted from the unit M₄. It is assumed that the PB code (f_n, f_n') relates to the first memory MEM₁ which stores the speech "I went to the supermarket". When the remote subscriber wishes to record his speech, he depresses the same PB code (f_n, f_n') again, and then his speech E₁ (I am going to my friend, Peter's house) is recorded in the area related to that PB code (f_n, f_n') of the unit M₃.
When a mother who is away from home wishes to know whether or not someone called her, she dials the system, and transmits the PB code (f , f_n') and another PB code (f_m, f_m'), and then she can listen to the content of the units M₄ and M₃ relating to the designated PB code (^f _n, ^f _n'). Hence, she can recognise that her son called her and left the message "I am going to my friend, Peter's house".
Furthermore, a remote subscriber can revise the speech recorded in the unit M₄ by transmitting the particular combination of the PB codes. In the above example, when the mother transmits the PB code (f , f_n,) which designated the area of the mother in the unit M₄, and another PB code (f_p, f_p'), the unit M₄ is ready to be revised by the remote speech. Then she says "Come back home as soon as possible. Dinner will be ready at six o'clock". When the son calls the system after the mother has.revised the content of the unit M₄, he listens to her revised speech "Come back home as soon as possible. Dinner will be ready at six o'clock", instead of the first speech "I went to the supermarket". Similarly, the son can record his speech again in the present system by operating the key pad which transmits the particular PB code.
As described above, in the adaptive oral communication mode, two remote persons can communicate with each other through the telephone answering system, even though they do not converse directly.
It should be appreciated that the units M₃ and M4 have a plurality of cells (MEM₁ to MEM_n), so a plurality of pairs of persons may communicate with each other. In this case, the combination of the PB codes may be kept secret from other persons to keep the conversation confidential.
In the above explanation, each memory cell (MEM₁ to MEM_n) records a single speech. When the speech is short, a memory cell may record two or more units of speech. In that case, an additional memory address designator (not shown) is provided to designate the start address of the selected memory to record the second speech in the same memory cell.
In the above embodinent it is preferable that each memory cell (MEM₁ to MEM_n) has the capacity to record speech equal to or longer than 60 seconds. The necessary capacity of a memory cell for recording each second depends upon the method of recording. When a frequency of 0.3-3.2 kHz is to be recorded, and the sampling frequency is 8 kHz, and each sample is quantized into 8 bits in a PCM coding system, 64 kilo-bits are necessary for recording each second. On the other hand, when the ADPCM (Adaptive Differential PCM) is used, 16-32 kilo-bits are enough to record each second.
A memory (MEM₁ to MEM_n) of each of the units M₁ to M₄ is implemented by a C-MOS memory, an N-MOS memory, or a bubble memory. When a semiconductor memory (C-MOS or N-MOS) is used, a power source backed up by a battery must be used, so that the content of the memories is not erased even when there is some trouble with a commercial power supply.
As described above in detail, according to the present invention a semiconductor memory is used to record speech instead of the previously-used magnetic tape. Therefore, no rewinding operation is necessary, and the speech is obtained merely by reading out the semiconductor memory. Further, an adaptive oral communication mode, in which two persons may communicate with each other through the present system is possible, by reading and/or revising the content of the memory.

Claims

1. A telephone answering and message recording system, including communication and control circuitry comprising a microphone (4); a speaker (5); an analog-digital converter (6) for converting an input analog speech signal from the microphone or from a telephone line to a digital signal; a plurality of groups (M₁,M₂,M₃,M₄) of semiconductor memories, each group having a plurality of memory cells (MEM_I- MEM_n); a group selection switch (6a) coupled to the output of the analog-digital converter (6) to select one of the groups; a cell selection switch (110,120,130,140) coupled to the output of the group selection switch (6a) to select one of the memory cells in each selected group; an output switch (7a) coupled to the outputs of the memories of the groups to select one of the groups; a digital-analog converter (7) coupled to the output of the output switch (7a), the output of the digital-analog converter (7) being coupled to the speaker (5); the system further comprising a call detector (2) to detect reception of a telephone call to initiate operation of the communication and control circuitry; a plurality of manual switches (21,22,23,24) for operating each group (M_l,M₂,M₃,M₄) of memories; and means (16) for controlling the operation of the communication and control circuitry according to a predetermined sequence.

2. A system according to Claim 1, wherein the microphone (4) and the speaker (5) are acoustically coupled to a handset of a telephone (1).

3. A system according to Claim 1, wherein the microphone (4) and the speaker (5) are electrically coupled to a telephone line through a switch.

4. A system according to any preceding claim, further comprising a PB receiver (40) coupled to the output of the microphone (4)to detect a PB (push.button) code to control the group selection switch (6a) and the output switch (7a) according to a PB code thus detected.

5. A system according to any preceding claim, further comprising a level detector (18) coupled to the microphone (4) to detect if the speech level is lower than a predetermined level; and a timer (19) to determine if the time during which the speech level is lower than the predetermined level is longer than a predetermined duration, in order to detect the finish of speech from a remote subscriber and to begin local speech.

6. A system according to any preceding claim, wherein in operation of the system one of the groups (M₁,M₂,^M ₃,^M ₄) is in a reading out mode, and another one of the groups is in a recording mode.

7. A system according to any preceding claim, wherein the system is first initiated to a fixed answering mode in which a group (M₁) is in a recording mode and a group (M₂) is in a reproducing mode; and wherein, upon receipt of a particular PB (push button) code which is detected by a PB receiver (40), the mode of the system is changed to an adaptive oral communication mode in which a group (M₃) is in a recording mode and a group (M₄) is in a reproducing mode.

8. A system according to Claim 4, wherein the selection of memory cells (MEM₁ to MEM_n) in the groups (M₃,M₄) is determined by a PB code which is detected by the PB receiver (40).

9. A system according to Claim 1, wherein the analog-digital converter (6) and the digital-analog converter (7) encode and decode, respectively, a PCM (pulse code modulation) signal, an ADPCM (adaptive differential PCM) signal or an LPC signal.